Summary: A precision pediatric oncology study has identified a dual-targeting therapeutic approach that may prevent relapse of medulloblastoma, the most common malignant childhood brain tumor. Although frontline therapies often shrink the primary tumor, about 30% of patients experience recurrence driven by a small, slow-dividing, therapy-resistant population of self-renewing tumor cells. The study shows that the FDA-approved compound pyrvinium, and a brain-penetrant derivative, can activate the protein CK1α to shut down two separate survival pathways—GLI and WNT—simultaneously, limiting the cells that drive relapse.
Key Facts
- The recurrence challenge: Medulloblastoma is the most common malignant pediatric brain tumor. While initial treatment often reduces tumor burden, roughly 30% of children experience relapse, and outcomes after recurrence are frequently poor.
- Hidden, therapy-resistant cells: A small subpopulation of slow-dividing, self-renewing tumor cells evades treatments aimed at fast-dividing tumor mass and can serve as the root of relapse.
- Dual-pathway survival: These relapse-driving cells rely on different signaling programs. The research targeted CK1α, a regulator that controls both the GLI pathway (promoting tumor growth) and the WNT pathway (supporting self-renewal).
- Pyrvinium’s mechanism: By activating CK1α, pyrvinium suppresses GLI-driven proliferation while also blocking WNT-dependent self-renewal, reducing the populations of cells that seed recurrence in preclinical models.
- Blood-brain barrier and delivery: Standard pyrvinium has limited brain penetration. The team developed and tested a modified, brain-permeable variant that reaches brain tissue and shows promising preclinical activity.
- Children’s long-term well-being: Targeted molecular approaches aim to reduce the severe developmental and late effects that can arise when adult chemotherapy regimens are adapted for young children.
Source: Medical University of South Carolina
Stopping cancer from returning is the focus of new work from MUSC Hollings Cancer Center, where researchers are targeting the cells that fuel recurrence of an aggressive pediatric brain tumor.
For many children with medulloblastoma, initial outcomes are encouraging. However, for roughly 30% of patients the disease returns, and relapsed tumors are often more difficult to treat. The new study, led by Jezabel Rodriguez-Blanco, Ph.D., at MUSC Hollings and the Darby Children’s Research Institute, explores a way to prevent those relapses by directly targeting the cells that survive standard therapy.
“Once the tumor comes back, long-term survival is close to zero,” said Jezabel Rodriguez-Blanco, emphasizing the urgent need to help patients at highest risk of relapse.
Published in Cell Death & Disease, the study identifies a strategy to reduce relapse by attacking the biology of the rare tumor cells most likely to survive therapy and drive regrowth.
Going after the root of relapse
The investigators focused on a small population of self-renewing tumor cells that divide more slowly than the bulk tumor and depend on distinct signaling pathways. Because many standard treatments target rapidly dividing cells, these slow-dividing cells can persist and later regenerate an aggressive tumor.
The team centered on CK1α, a protein that influences both GLI signaling (which drives tumor proliferation) and WNT signaling (which supports self-renewal). Earlier work showed GLI inhibition can slow tumor growth; this study extends that concept by using CK1α activation to hit both GLI and WNT simultaneously.
Pyrvinium, an FDA-approved compound already recognized for destabilizing GLI via increased CK1α activity, was tested alongside a brain-permeable derivative. In mouse and patient-derived models of the SHHα subtype of medulloblastoma, pyrvinium suppressed GLI-driven proliferation of Sox2⁺ cells and, importantly, also reduced CD15⁺ cells linked to WNT-dependent self-renewal. The combined effect reduced tumor stemness, impaired tumor engraftment, prolonged time to relapse, and lowered relapse risk in preclinical tests.
“Cancer cells are adept at escaping when you block a single pathway,” Blanco said. “Targeting both pathways at once gives us a much better chance of preventing recurrence.”
Promising — but early — progress
Although results in preclinical models are encouraging, researchers caution that this approach remains at an early stage. A key obstacle is drug delivery: standard pyrvinium does not efficiently cross the blood-brain barrier. To address this, the team developed a modified, brain-penetrant compound that shows promising distribution and activity in the brain.
The next steps include optimizing the brain-penetrant derivative for safety and efficacy in children and advancing toward clinical testing. If successful, such targeted CK1α-activating therapies could reduce the late effects associated with conventional, non-selective treatments and improve long-term outcomes for pediatric patients.
“This work shifts the focus from simply shrinking tumors to preventing them from coming back,” Blanco said. “By attacking the cells that seed relapse, we have a real opportunity to change outcomes for these children.”
Key Questions Answered:
A: Standard therapies target fast-dividing tumor cells, shrinking the main mass but often missing a small population of slow-dividing, self-renewing cells. Those surviving cells can resist treatment and later drive aggressive relapse.
A: Pyrvinium activates CK1α, which simultaneously suppresses GLI signaling that promotes growth and WNT signaling that supports self-renewal. Blocking both pathways reduces the tumor’s ability to escape and regenerate.
A: The main limitation is brain delivery. In its original form, pyrvinium poorly penetrates the blood-brain barrier. The research team developed a brain-penetrant variant and continues to refine it for safety and effectiveness in children.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The original journal paper was reviewed in full.
- Additional context was added by staff for clarity.
About this brain cancer research news
Author: Leslie Cantu
Source: Medical University of South Carolina
Contact: Leslie Cantu – Medical University of South Carolina
Image: Image credited to Neuroscience News
Original Research: Open access. “CK1α agonists attenuate medulloblastoma stemness and relapse risk” by Kendell Peterson et al., published in Cell Death and Disease. DOI: 10.1038/s41419-026-08762-6
Abstract
CK1α agonists attenuate medulloblastoma stemness and relapse risk
While most children with medulloblastoma have relatively favorable outcomes, patients in the Sonic Hedgehog (SHH) subgroup with TP53 mutations (SHHα) face a worse prognosis and higher relapse rates. The authors previously identified a non-canonical, Gli-driven Sox2⁺ cell population that promotes relapse in SHH medulloblastoma. Because few Gli-targeting strategies have shown clinical promise, this study evaluates pyrvinium and a brain-permeable derivative (SSTC3) for effects on stemness and relapse risk in mouse and human-derived SHHα models.
The researchers found that pyrvinium suppresses Gli-driven proliferation of Sox2⁺ cells and, unlike other SHH/Gli-targeting approaches, also impairs self-renewal by depleting CD15⁺ cells. Mechanistic studies indicate that CD15⁺ self-renewal is WNT-dependent and linked to loss of p53/microRNA-34a-mediated repression of WNT signaling.
Both pyrvinium and SSTC3 reduced Sox2⁺, CD15⁺, and dual-labeled populations in mouse and patient-derived SHHα models and impaired primary and secondary tumor engraftment. The data establish CK1α as a therapeutically relevant vulnerability and support development of brain-penetrant CK1α-targeting derivatives, since pyrvinium itself is not an ideal clinical candidate.